The present invention relates to a method and apparatus for decontaminating a medical instrument that has two or more parts that can move relative to one another in use. The invention is particularly, although not exclusively, applicable to the decontamination of surgical instruments. However the invention may also be used in the decontamination of other types of medical instrument, or other medical or surgical equipment or components having relatively movable parts. The present invention is applicable to the decontamination of medical instruments for use in any medical field, including dental and veterinary fields. The present invention relates to the automatic decontamination of medical instruments using a decontaminating apparatus.
Although the medical instruments may be constructed to be non-disposable, the present invention may also be used to decontaminate disposable instruments, which in many cases are too expensive to be disposed of after a single use. For example, the invention may be used to decontaminate so-called “reposable” instruments, which are limited to a certain number of uses e.g. 10 uses. Thus, the invention may be applied to non-disposable, disposable or semi-disposable or reposable instruments. Thus, the invention is broadly applicable to the decontamination of reusable medical instruments.
In decontaminating reusable instruments, it is important that all external surfaces of the instruments are thoroughly cleaned to remove any body fluids, proteins, tissue or bone fragments etc. Where an instrument includes an internal passageway, such as a tubular bore or cavity, the internal surfaces may also need to be cleaned. Cannulae and lumened instruments are examples of medical instruments having internal passageways to be cleaned. It is often desirable to disinfect instruments during the decontamination process to reduce the risk of transmitting infection between patients. Instruments may undergo sterilization as a final decontamination stage.
Decontamination may involve forcing pressurised fluid over the instruments to achieve cleaning. Disinfection may also be carried out in this way using fluid at an elevated temperature. The fluid may be water or may be a decontaminating fluid including one or more decontaminating agents. This so-called “deluge decontamination” is typically carried out in large deluge washer machines which spray fluid over the instruments in a similar manner to a dishwasher machine. Medisafe UK Limited's Niagara® range washers, e.g. the Niagara® Express, are examples of deluge decontamination systems. The machines may include flushing attachments to which cannulated instruments may be attached to permit decontamination of internal surfaces. One example of such an attachment is found in EP 0822869A1 entitled “Method and Apparatus for Cleaning Hollow Elements” filed on 19 Apr. 1996, with priority date of 24 Apr. 1995. The attachment described in this earlier document is arranged to provide a continuous pulsed flow of fluid to the interior of an instrument.
Alternatively or additionally, decontamination of medical instruments may involve the use of ultrasonic waves. In an ultrasonic decontamination process, the instrument is immersed in a bath of decontamination fluid. Ultrasonic transducers are used to excite fluid in the bath, causing ultrasonic waves to propagate through the fluid. The ultrasonic waves cause small, high pressure bubbles to form and collapse in the fluid at high frequency. This “cavitation” effect gives rise to pressure waves in the fluid, which acts to “scrub” the surfaces of the immersed instrument. In this way, debris attached to the surfaces of the instrument may be loosened. Fluid may be supplied to internal surfaces of the instruments during ultrasonic cleaning. Instruments may also be subjected to soaking in which they are immersed in fluid e.g. provided in an ultrasonic reservoir, but without the application of ultrasonic waves.
Ultrasonic decontamination may be carried out alone, or in combination with deluge decontamination. Deluge decontamination may be used to help flush debris dislodged by the ultrasonic decontamination from the surfaces of the instrument. Combined ultrasonic and deluge decontaminating washers are known. Examples include Medisafe UK Limited's Niagara® SI Ultrasonic® and Niagara®, SI PCF® machines. These machines include an ultrasonic reservoir situated in the base of a decontamination chamber, with deluge sprayers arranged above the reservoir. Instruments are inserted into the chamber at various levels. This may be achieved by placing the instruments directly on a carrier of the machine, or by first placing them in baskets which then placed on the carrier. The lowermost instruments may be immersed in the ultrasonic reservoir to enable ultrasonic decontamination to be carried out. This may be achieved by lowering the carrier appropriately and/or filling the ultrasonic reservoir with fluid to cover the instruments. The bath may or may not then be drained and/or the deluge sprayers operated. Operation of the deluge sprayers may provide deluge decontamination of those instruments situated in the upper parts of the decontamination chamber, and in some cases, the ultrasonically decontaminated instruments in the reservoir if drained. In other situations, decontamination may involve ultrasonic decontamination without deluge decontamination. Examples of such ultrasonic decontamination machines include Medisafe UK Limited's Sonic Irrigator® range e.g. the Sonic Irrigator® SA® and Sonic Irrigator® PCF®.
In general decontamination may include any or all of deluge decontamination, which may include pre wash, wash and rinsing stages, ultrasonic decontamination, soaking, disinfection, and sterilization.
Certain medical instruments include parts that are moved relative to one another in use e.g. when the instrument is manipulated or actuated. For example, an instrument may have a working portion having parts that are movable relative to one another to change a configuration thereof in use, or which working portion includes one or more parts that are moved relative to another part of the instrument e.g. to articulate or otherwise move the working portion. Decontaminating instruments of this type presents particular challenges to achieve adequate decontamination of all surfaces of the instruments given that relative movement of parts of the instrument will expose different surface to contaminants in use.
These issues may be encountered with any instrument having relatively movable parts, ranging from articulated instruments of a simple forceps or scissor-like form to more complex instruments which are increasingly used in surgery. Such complex instruments may be used e.g. in laparoscopic or minimally invasive procedures, and/or robot assisted procedures. A “complex” surgical instrument typically includes a working portion whose manipulation can be remotely controlled via an operating portion remote from the working portion. In many arrangements an operating portion is provided at a proximal end of an instrument, which instrument has a working portion or working end at a distal end. Manipulation of the working portion may, for example, involve relative movement between a part of the working portion and another part of the instrument to result in articulation of the working portion, or between parts of the working portion to provide actuation thereof e.g. to provide a grasping or cutting action. Some complex surgical instruments include a working portion comprising an end effector at the distal end of the instrument connected via a “wrist” to a shaft, providing various degrees of freedom of the end effector.
Control of the operating portion may be achieved directly by the surgeon manually manipulating an operating interface or one or more handles of a handle portion of the operating portion, or by coupling an operating interface of the operating portion to a robotic arm, which is controlled by a surgeon e.g. using a computer or movable input device such as a joystick. An operating portion may be connected via an operation transmission arrangement to the working portion for communicating an operation indicated at the operating portion. The operation transmission arrangement might comprise cables or a rod etc.
It will be appreciated that in addition to relative movement between parts of such instruments at the working end or portion, in remotely operated instruments there is typically also relative movement between parts of the operating portion and operation transmission arrangement involved in manipulating the instrument in use. Ensuring that all surfaces that may be exposed during manipulation, including those of the operating portion and operating transmission arrangement are adequately decontaminated presents further challenges.